The Clinical Cryobiology Laboratory will function as a core resource for this project by providing all marrow and peripheral blood stem cell processing and storage, and progenitor cell culture as appropriate. Specific Aim 1 will be to provide this marrow processing including tumor- cell depletion. Both immunologic and pharmacologic techniques will be used for marrow purging. A clinical trial of CD34-enrichment will be continued. Uniform marrow processing with appropriate quality is vital to clinical protocols studying engraftment kinetics or disease-free survival. This laboratory will collate data regarding the marrows including cell quantities and differentials, progenitor cell quantities, and purging results. Specific Aim 2 will be to develop models predictive of engraftment to serve as a database for the research studies, and for the development of new processing and cryopreservation techniques. Quantification of hematopoietic progenitors by analysis of cell phenotype will be studied as an alternative to cell culture for this modelling.